This will be a bit of a work-in-progress. I may add to these as I go along and find new games.
If you have some recommendations to add, please do so in the comments section below.

Sidescrolling Action & Adventure

Featured Game: Top Hunter – Roddy & Cathy
The game is beautiful. What first hit me was the detailed backgrounds and how the game was built. There are 2 layers of backgrounds, which gives this game a 3D feeling. The backgrounds move in different speeds while you walk in the game, just like cartoons on TV. And later I understood what the real purpose of the backgrounds where! You can jump in and out between the backgrounds and you can go in front of a tree or take the way behind of the same tree. This gives a whole new and unique dimension in a 2D game.

The game idea reminds little of the NES’s “Super Mario Bros.” You can jump on the enemies and they get flattened and die. You can also hit and (when holding the A button) grab, pick up and finally throw them. When throwing an enemy at another, you kill both, simple! You can make special attacks too. Like in Street Fighter, you can throw a fire ball. You can dash and when in air you can strike down. All this makes the game play flexible. The special moves are not 100% though. Sometimes they just don’t want to work. Bad control? Well it gets little frustrating when you know that you made the move exactly right and nothing happened. In tense situations, it makes you mad.”Neo-Geo.com’sReview of Top Hunter

Run N Gun

Featured Game: Shock Troopers
” The control is great once you get used to the firing system, and rolling is a great way to dodge enemy bullets. You really feel like have control of your character, and this just makes the game a blast to play.

You also have the option of rushing through the levels quickly, or taking your time and trying to kill enemies with close-range attacks. Personally I find the game to be much more fun the latter way, but it’s totally up to the player as to how fast you want to proceed through the game. Just keep in mind that the journey is more important than the destination… not to mention that rushing through the levels gives you less time to enjoy the music.”Neo-Geo.com’s Review of Shock Troopers

2D Fighting

Featured Game: Waku Waku 7
“Big, colorful cartoony graphics saturate the world of Waku Waku 7. The characters are well drawn and their respective backgrounds are equally animated and creative. No ultra-serious martial arts masters in this one. If you’ve never seen a giant monster-bunny and a little girl go toe-to-toe with a pair of midgets in a walking tank, then you’re in for a treat!

Like any good game (video game or otherwise), Waku Waku 7 is easy to learn, and nearly impossible to master. With so many special
moves, super moves, and other secret attacks -it will keep you busy and coming back for more. It’s even more fun with friends.

Wow, what more can I say? All that keeps this game from a perfect score is its limited amount of characters -a minor complaint indeed! Waku Waku 7 is like a really good movie you wish would never end. Unfortunately, its also a very hard game to come by, but if you are lucky enough to get your hands on a copy play it, play it, play it (you won’t be forcing yourself) -and by golly, make other play it too. You owe it to the world. ”Neo-Geo.com’s Review of Waku Waku 7

2D Shmups

Featured Game: Pulstar
“With the Neo Geo being home to a fair few decent shooters, this game stands out as being one of the best. You actually need to use skill to get through each level, unlike games such as Zed Blade, where you just hold the fire button down and hope for the best. The game may be uncompromisingly tough, but if you memorise the set attack patterns (which are basically the same each time) you can progress through each level using pure skill (well, maybe a little luck sometimes 🙂

The only problem really is that when you die you lose most of your weapons, but you can usually pick some more up quite quickly. Luckily it doesn’t put you back too far in the level either if you bite the bullet. You may also notice the similarities between this and the R-Type games. Yes, it is true that they are similar (for instance the shield that you have on the front of the craft and some of the levels look very familiar!), but don’t let that fool you into thinking that this is just a cheap rip off. Most shoot ’em ups play in a similar way to each other, so it doesn’t really matter too much.”NeoGeoForLife.com’s Review of Pulstar

Puzzle/Maze

Featured Game: Magical Drop 3
“Everything that worked in MD2 is back–the lighting-fast decision making, the frenzied action, and the tight control. Magical Drop III is one of the fastest puzzle games, period, and players will often feel like they’re just barely hanging on–which is a very good thing. And for once, twitch gamers who do venture into puzzle territory will find they can apply their skills immediately. MD3 rewards smarts and speed equally.

Hey, there’s a reason there’s no Magical Drop IV. Magical Drop III makes for a fitting, satisfying final game in the series simply because it gets everything right. It’s truly a must-own for rabid puzzle fans.”Neo-Geo.com’s Review of Magical Drop 3

Sports/Racing

Featured Game: Super Baseball 2020
“Unlike most sports games that set themselves in the future, Super Baseball still maintains what makes the sport enjoyable to play in backyards. The changes to the rules make sense, and haven’t been switched or manipulated simply to make it different. The same number of players enter the game, there are still three strikes, and blasting a shot out of the park is still a homerun… almost.

The major change, aside from the players, is the field of play. A homerun is only good for a run if it hits a specific spot in centerfield. Foul balls are only such if they pop behind the batter. Everything else is fair game, off the glass-topped stands or not. The
field will eventually be filled with mines (!), so it’s imperative to watch your step.”DigitPress’s Review of Super Baseball 2020

Other

Featured Game: Windjammers (Flying Power Disk)
“The gameplay of Windjammers is obviously inspired by Pong (with an Air-Hockey feel to it), but adds some great elements in order to make
it more attractive to modern gamers. The premise of the game is basically playing a tennis-like game with a Frisbee.

Two players go head to head to try to throw the Frisbee past the other player. You receive 3 points for hitting the large center target and 5 point for hitting the smaller upper and lower targets. The areas are walled in and some courts have other barriers added to them. These allow you to bounce your disc creatively to fake out your opponent. This adds a great deal of strategy and the necessity for quick reflexes.

Windjammers is a must-have for Neo-Geo owners and worth emulating if you don’t have the system. There is enough technique in Windjammers to keep hardcore gamers happy and it is simple enough to be inviting to casual gamers.”Racketboy’s Review of Windjammers

At first I was looking for Windjammers, and was pleased you named it. It is a BLAST.

The problem with the list is that Magical Drop is not as cool as Money Puzzle (Idol) Exchanger. Cooler music, cooler characters, crazier gamneplay. Coolest character names OF ALL TIME. It is about time Exchanger got the props she deserves!

There are a lot of people that don’t know the game exists, or that it’s even connected to the FF series because of the name. Couldn’t tell you how many times I’ve seen people on Shoryuken say they’ve never played it or even heard of it – as observed when a recent combo video named “Last Order” was released for it and frontpaged on SRK. The game only has about 10-20 players on GGPO compared to 3S having close to 150 or KOF98 having over 200 players. It’s not so much a hidden gem as it’s underappreciated by the fighting game community – that’s why I think it should be up there. Poor marketing at the end of an era when fighting games were losing popularity and SNK was bankrupt are the primary reasons for this. Most agree that it’s a great game, but if that’s the case, why so few players?

By under-appreciated, I just mean under-played and under-promoted; this game never got any love at EVO and was/is only popular in Japan, where they still hold tournaments for it. There are side tournies at EVO, but the turn-outs are only about ten people. :/

I don’t disagree with Waku Waku 7 in actuality, but if I had to pick one under-appreciated fighting game to represent the Neo-Geo – I’d always pick MOTW. Personally, I’d even consider the SS series to be hidden gems at this point, because those games have even less players.

I really love all the hidden gem collections its helped me find some games I’ve been looking for. One thing I just noticed is under the “Side Scrolling Action/Adventure” section of the “Neo-Geo Hidden Gems Collection” under more great games you have “Ninja Commando” listed when I believe it should be “Ninja Combat”. As “Ninja Commando” is a “Run N Gun” game which is also listed in this article.